1. Field of the Invention
The invention relates to the reinforcement of pistons of aluminium or aluminium alloy and in particular to the reinforcement of crowns of such pistons.
Because of their comparatively light weight, aluminium and aluminium alloys are commonly used in the manufacture of pistons for internal combustion engines. They suffer, however, from the disadvantages that, as compared with many other metal materials, such as ferrous materials, they do not wear well and are not well able to withstand elevated temperatures. The most arduous conditions encountered by an internal combustion engine piston are at the crown end of the piston which, in use, bounds the combustion chamber, since it is in the combustion chamber that the highest temperatures are found.
2. Review of the Prior Art
Accordingly, there have been various proposals for reinforcing crowns of aluminium or aluminium alloy pistons to render them better able to withstand these conditions. In all such cases, however, there has been the problem of connecting the reinforcing materials securely to the aluminium or aluminium alloy because aluminium does not readily bond to many reinforcing materials and a strong bond is essential, since any failure of the connection can have far reaching consequences.